Ram air turbines (RATs) are commonly used on modern aircraft to provide a secondary or emergency power source in the event the primary power source is insufficient or fails. A typical ram air turbine includes a turbine that remains internal to the aircraft body until additional power is needed. When additional power is required, the RAT receives a deployment signal that releases stored energy contained within a deployment actuator. The force from the actuator opens a door(s) in the aircraft fuselage, deploying the ram air turbine into the freestream air adjacent to the aircraft. The turbine is rotated by the freestream air and the rotational torque from the turbine is transferred through a drivetrain to be converted into electric power by a generator. The rotation from the ram air turbine may also be used to drive a hydraulic pump. Ram air turbines utilizing both an electric generator and a hydraulic pump are referred to as hybrid ram air turbines. Some existing hybrid ram air turbines connect the drive train to a multi-output gear set that simultaneously drives the hydraulic pump and the generator off of the drive shaft. In alternative hybrid ram air turbines, a single shaft can be utilized to directly drive both the hydraulic pump and the generator.
When deployed, the ram air turbine must be spaced apart from the body of the aircraft by a sufficient margin to ensure that the turbine blades don't contact the aircraft body, or otherwise interfere with the aircraft body. In some examples, ram air turbines ensure that the turbine is sufficiently spaced apart by including a spacer strut between the generator and/or the hydraulic pump and the turbine portion of the ram air turbine. In existing hybrid ram air turbine configurations, the hydraulic pump and the electric generator are mounted at one end of the strut, while the turbine portion is mounted at the other end of the strut, opposite the generator and the hydraulic pump. The spacer strut structurally supports the turbine portion, relative to the aircraft as well as providing additional clearance.